Microsensors to Give Food its Own Voice

The Internet of Things brings the smallest devices online. Now its influence is set to reach the food chain through a new generation of microsensors.

In a few years time, the ritual of going to the fishmongers and checking the freshness of the goods on display could face stiff scientific competition. Perhaps we are not too far away from using a smartphone—or whatever device is available by that time—to receive all the information about how fresh is our food. We will not only know if that tempting seabass at the stall was fished yesterday, but also if the cold chain was broken at any given moment. The technology to achieve such level of monitoring could be based on the microsensors developed by a group of Swiss researchers.

At ETH Zurich, a historic university research center founded in 1885, they have developed a microsensor prototype that, achieving an extremely reduced thickness of 16 micrometers, between 5 and 10 times less than a human hair, can be used in the food industry without posing any health risks. Key for that is its biodegradable and biocompatible material. By using an electrical filament made of magnesium, silicon dioxide and nitride enclosed in a compostable polymer, the team lead by Giovanni Salvatore has developed a technology that dissolves without leaving a trace in a matter of days. However, despite its brief work life, it could well trigger a revolution in the way we process, transport and distribute food.

Salvatore, who has published his contribution in the Advanced Functional Materials magazine together with a group of researchers, illustrates the potential of the technology through the transport of fish. The new microsensors could be used to check if the fish brought to Europe all the way from Japan has maintained the right temperature along the whole journey. Once the goods arrived at their destination, the microsensors would transmit a kind of logbook regarding the cold chain. Later, in the final stage of the fish's journey from boat to plate, the sensors would have dissolved completely. With their current width, the sensors can remain operational for a whole day, although their autonomy could be augmented by increasing the polymer’s thickness. Another advantage of the technology is that it can be folded and stretched without losing any of its functionality.

At present, it uses a micro battery attached through extremely thin and biodegradable cables. The system has its own processing unit that transmits all the temperature data via Bluetooth. However, at ETH, they are already working on an integrated and biodegradable power source that would soon allow to do without such external unit.

Fish could just be the start of a microsensor era

Biodegradable microsensors will go beyond fish, as they can also be used with other perishable foods such as fruit and vegetables. It is also foreseeable that, in the long run, this technology will provide information concerning their degree of ripeness by measuring the gases they release in the process like these smart labels already do. All this will help to improve food safety, but will also help to manage resources in a more efficient and rational way.

As can be seen, not even food can escape from the ecosystem of connected devices ushered in by the post-PC era, which will mean a digitally hyperconnected world even at microscopic levels.

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